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This study deals with the analytical investigation of oscillatory squeeze film flow through a Brinkman viscoelastic Oldroyd-B fluid-saturated porous layer subject to two vertically harmonically oscillatory disks. The validity of the present proposed analytical solutions is first demonstrated for the Newtonian fluids when both Λ1 and Λ2 tend to zero by comparison with the previous literature. Results demonstrate that an increase in the elasticity parameter Λ1 correlates with a rise in axial velocities, indicating that the relaxation time Λ1 facilitates enhanced squeeze flow. In the case of squeeze film flow in porous layers, low oscillating frequencies exert minimal effects on axial velocities, independent of variations in the viscoelasticity parameter Λ1. However, at higher oscillating frequencies, axial velocities escalate with increasing the viscoelasticity parameter Λ1. Furthermore, the retardation time Λ2 of the viscoelastic fluid shows no significant effect on the axial velocity, regardless of oscillating frequency changes in both pure fluids and porous layers. [ABSTRACT FROM AUTHOR]

The 3D printing of continuous carbon fiber reinforced thermoplastics can widen their applications and allow the construction, on the fly, of complex composite parts. In this work, we model the consolidation of tapes through deformation and resin flow during robotic 3D printing of continuous carbon fiber low-melt poly aryl ether ketone (CF-LM PAEK) thermoplastics. Unidirectional tensile specimens per ASTM D3039-17 with a modified thickness (three tapes and two layers) are fabricated. The modeling effort of the squeeze flow involved in the process uses the anisotropic fluid model known as the Ericksen flow model. The proper generalized decomposition is used to simulate the tows deformation and the fluid flow while using an in-plane-out-of-plane decomposition. The modeling is validated with cross-section microscopy of the 3D printed specimen. Cross-ply and staggered tape deposition are explored as well. [ABSTRACT FROM AUTHOR]

The unsteady magnetohydrodynamics (MHD) flow and radiative thermal transfer of viscous and Casson hybrid nanofluid through two surfaces in a permeable medium with chemical reaction are studied. The hybrid nanoparticles of alumina Al 2 O 3 and copper ( Cu ) are dispersed in the base fluids of water and sodium alginate (C 6 H 9 N a O 7) . The discretize equations are solved by implementing similarity variables and Keller-box methods. The comparison of the current results with the published results for validation is discovered in proper agreement. The impacts of squeeze, magnetic, porous media, chemical reaction, nanoparticles volume fraction and thermal radiation on behavior and physical quantities of flow are discussed. The graphical results show the wall shear stress, convective thermal and mass transfer of Casson hybrid nanofluid is greater than viscous hybrid nanofluid. The squeeze of two surfaces accelerates the fluid velocity, while it slows down in the middle of channel when Ha , Da , and ϕ 2 increases. The reduction of convective thermal transfer and temperature discovers when R d and ϕ 2 escalates. The concentration enhance and rate of mass transfer reduce with the constructive chemical reaction, whereas contrary effects is shown for destructive chemical reaction. [ABSTRACT FROM AUTHOR]

This paper explores the magnetohydrodynamic (MHD) squeeze flow of an electrically conducting fluid between two infinite parallel disks with a perpendicular magnetic field. The study focuses on the case where the upper disk moves towards a stationary lower disk. By employing similarity variables, we reduce the MHD momentum and continuity equations into a fourth-order linear boundary value problem, solved using a modified operational matrix method. The numerical approach is validated through L2-truncation error analysis, boundary condition comparisons, and by comparing results with other methods like HAM, HPM, and bvp4c that produce analytical and numerical solutions. Graphical analyses reveal the effects of the squeeze number, Hartman number, and the boundary parameter on velocity and flow profile. Results indicate that the Hartman number significantly affects the velocity due to the Lorentz force, while the squeeze number and boundary parameter influence the velocity and flow profile differently in suction and injection cases. The numerical solution demonstrates high accuracy and convergence compared to previous methods in terms of absolute error.

AbstractTransferring biological fluid through arteries is a topic that has garnered serious interest in recent times, especially when it pertains to applications such as drug delivery. In our body, arteries serve as the primary conduits for blood flow and this study aims to model the blood flow in this situation. The working fluid is essentially pure blood, which acts as a base fluid, supplemented with nanoparticles of Titanium Dioxide (TiO2) and Gold (Au). Nanoparticles could change the thermal and rheological properties of blood which might be particularly advantageous for ensuring smoother flow or optimal distribution of drug molecules within the bloodstream. In the present work, a porous channel is considered with parallel walls that exhibit varying permeability on boundaries. Such a design enables the nanoblood to enter and exit the channel, mimicking certain natural processes like transvascular fluid exchange. Additionally, the variable height of the channel that expands and squeezes uniformly could be reminiscent of the pulsatile nature of blood flow seen in our arteries due to heartbeats. To understand the dynamics of this hybrid nanoblood flow, the governing equations are converted into a set of nonlinear ordinary differential equations using the similarity transformation approach. For solving these transformed equations, the research harnesses the BVP4C built-in function in MATLAB software. Through this computational approach, the research provides insights into the velocity and temperature profile of the fluid, the distribution of normal pressure, wall shear stress, and the Nusselt number concerning various parameters. The findings of the present study can be significant and useful in biological sciences and technologies and the detailed results are presented completely in the article’s body. [ABSTRACT FROM AUTHOR]

Abstact: Detailed investigation has been carried out to examine the behavior of squeezed fluid flow under the magnetic influence amid two infinitely extended disks arranged parallel to each other. Porosity is introduced in the lower disk to study the fluid flow characteristics. Applications in engineering and industrial processes, such as cooling systems and chemical reactors, where magnetic fields regulate fluid flow, need a thorough understanding of this phenomenon. The funamdental equations of Navier Stokes (N-S) Equations in the form of Partial Differential Equations (PDEs) are transformed into Ordinary Differential Equations (ODEs) with the help of similarity tranformation. For ensuring better accuracy MATLABs powerful tool is employed in the form of BVP4C technique, to compute the numerical solution. Fluid flow characteristics are discussed for the stated geometry. The velocity profile is discussed under variations of Non-dimensional parameters (Hartman Ha, Squeezed S, suction / injection A). Major findings of the current research revealed that the effect of the Hartmann Number on greatest value of velocity profile is more remarkable in the case of injection compared to suction. Moreover, Velocity profile exhibits a consistent increase as η rises in both scenarios without injection (A = 0) and with injection (A < 0). Current study opens new avenues in terms of exploration of fluid flow characteristics in context of simplicity, accuracy and verstality of numerical techniques.

Squeeze flow has been proven as an interesting technique for the rheological evaluation of many classes of materials, being relatable to common compressive phenomena from various processing and application procedures. Despite the simplicity of the experimental setup needed to run it, the results from the test are rather complex, involving multiple variables and factors that are not fully clarified by the bulk stress response. One additional piece of information that can be valuable is the pressure distribution over the sample area, since it is related to key aspects of the flow. The addition of a pressure mapping system to the traditional setup of the test has been recently proposed as a way to enrich the information obtained, in a method deemed pressure mapped squeeze flow (PMSF). This paper presents the evolution and state of the art of this technique, and analyzes a plastic clay with two different water contents in three displacement rates to demonstrate the potential and possibilities that PMSF offers. The experimental setup is presented in detail, along with the calibration procedure and data treatment suggested, as well as multiple types of analyses including bulk stress curves, raw pressure distribution plots, measured contact area, evolution of the mean profile, comparison to theoretical models supported by error analysis, and investigation of variation over the area. With the procedure established and presented in this work, it should be possible to apply PMSF as a valuable technique throughout the materials science and engineering community. [ABSTRACT FROM AUTHOR]

This study explores cost-effective and customized composite applications by strategically placing carbon fiber-reinforced thermoplastics in multi-material designs. The focus is on developing a model for the simultaneous processing of non-reinforced and reinforced thermoplastic layers, with the aim of identifying essential parameters to minimize insert flow and ensure desired fiber orientation and positional integrity. The analysis involves an analytical solution for two layered power-law fluids in a squeeze flow setup, aiming to model the combined flow behavior of Newtonian and pseudo-plastic fluids, highlighting the impact of the non-Newtonian nature. The behavior reveals a non-linear trend in the radial flow ratio towards the logarithmic consistency index ratio compared to a linear trend for Newtonian fluids. While a plateau regime of consistency index ratios presents challenges in flow reduction for both layers, exceeding this ratio, depending on the height ratio of the layers, enables a viable overmolding process. Therefore, attention is required when selectively placing tailored composites with long-fiber-reinforced thermoplastics or unidirectional reinforcements to avoid operating in the plateau region, which can be managed through appropriate cavity or tool designs. [ABSTRACT FROM AUTHOR]

We propose a methodology for the rheological characterization of a semisolid metal slurry using experimental squeeze-flow data. The slurry is modeled as a structural thixotropic viscoplastic material, obeying the regularized Herschel–Bulkley constitutive equation. All rheological parameters are assumed to vary with the structure parameter that is governed by first-order kinetics accounting for the material structure breakdown and build-up. The squeeze flow is simulated using finite elements in a Lagrangian framework. The evolution of the sample height has been studied for wide ranges of the Bingham and Reynolds numbers, the power-law exponent as well as the kinetics parameters of the structure parameter. Systematic comparisons have been carried out with available experimental data on a semisolid aluminum alloy (A356), where the sample is compressed from its top side under a specified strain of 80% at a temperature of 582 °C, while the bottom side remains fixed. Excellent agreement with the experimental data could be achieved provided that at the initial instances (up to 0.01 s) of the experiment, the applied load is much higher than the nominal experimental load and that the yield stress and the power-law exponent vary linearly with the structure parameter. The first assumption implies that a different model, such as an elastoviscoplastic one, needs to be employed during the initial stages of the experiment. As for the second one, the evolution of the sample height can be reproduced allowing the yield stress to vary from 0 (no structure) to a maximum nominal value (full structure) and the power-law exponent from 0.2 to 1.4, i.e., from the shear-thinning to the shear-thickening regime. These variations are consistent with the internal microstructure variation pattern known to be exhibited by semisolid slurries. [ABSTRACT FROM AUTHOR]

Abstract The influence of the combined addition of cellulose fibers (FC) and microcrystalline celluloses (MCC) on the fresh properties and hydration kinetics of cementitious composites was investigated. For this purpose, sixteen different formulations of FC-MCC celluloses in the cement matrix were analyzed, in which various cellulose fibers were 0.5%, 1.0%, and 1.5% and microcrystalline cellulose in 0.4%, 0.6% and 0.8% about the cement mass. The cementitious composites with the addition of FC-MCC celluloses were characterized in terms of rheological behavior, which was determined through the Squeeze flow method, fluidity through the mini-slump test, and hydration kinetics determined through the temporal evolution of the temperature of the mixtures. The initial hydration tests showed that the maximum addition of MCC (0.8%) used in this work reduced the maximum temperature of the cementitious composites, as well as the combination of FCs with MCC 0.8. Cellulose fibers took a longer time to reach the maximum temperature. The combined contents of FC 1.0-MCC 0.4 and FC 0.5-MCC 0.6 promoted an increase in the maximum temperature, which could indicate a dispersive effect of the cellulose particles with the cementitious system. The results of the compression flow showed that the studied samples presented a flow with very low loads and extended for a large part of the curve. Te increase in the amount of cellulose fiber alters the main phenomena related to flow: with a high cellulose content (FC 1.5%) there is an increase in friction between the particles, leading to the conclusion that the amount of cellulose fibers in the cementitious system influences on the rheological behavior and the occurrence of phase separation.

The development of microfabrication and surface machining techniques has made solid surfaces more precise, and the gap dimensions in mechanical systems such as Micro Electro Mechanical Systems and Micro Total Analysis Systems have decreased from the order of micrometers to the order of nanometers. Because the fluid flow properties in nanogaps are different from those in the bulk, experimental measurement of flow velocity in nanogaps is necessary to design nanogap mechanical systems and verify the principle of their operation. In general, the lateral flow velocity distribution can be measured by mixing fluorescent particles with the fluid and tracking the particles with a microscope with high lateral and temporal resolution. However, in previous studies, quantitative measurement of flow velocity in nanogaps could not be achieved due to the influence of the interaction between the fluorescent particles and solid surfaces because the diameters of the particles were large, and ranged from tens of nm to tens of µm. The objective of this study is to quantitatively measure the lateral flow velocity distribution in nanogaps by particle image velocimetry using quantum dots with diameters in the single-digit nanometer range. We have implemented a simultaneous quantitative measurement of the nanogap shape by optical interferometry, and the flow velocity distribution by PIV using quantum dots. Focusing on the squeeze flow caused by narrowing the gap, we have shown that PIV using quantum dots can achieve quantitative measurement of velocity distribution in 100 nm-level-gaps. [ABSTRACT FROM AUTHOR]

Ice skates are remarkably slippery across a wide range of conditions. We propose, based on earlier observations and new modeling, that an ice-rich slurry forms rapidly beneath a skate blade during each stride to lubricate the interface. Crushing from normal load and abrasion from sliding provide ice particles and heat to the slurry, with average contact pressures approaching melting pressures for the bulk ice. Shearing of the slurry by forward motion generates additional heat to melt the ice particles at the pressure-reduced temperature. We model these mechanics and link the viscosity of the resulting slurry to its ice fraction, which controls slurry-film thickness via lateral squeeze-flow. The slurry properties quickly converge to establish a highly efficient lubricating film that provides the characteristically low skate friction across a wide range of conditions. Although our 1D model greatly simplifies the complex interaction mechanics, its predictions are insensitive to most assumptions other than the average contact pressure. The presence of ice-rich slurries supporting skates merges pressure-melting, crushing, abrasion and lubricating films as a unified hypothesis for why skates are so slippery across broad ranges of speeds, temperatures and normal loads.

The rheometric techniques available for the evaluation of mortars involve a different set of flow conditions. Squeeze flow is based on the compression of the sample with gap reduction and geometric restrictions, providing important information even when phase separation occurs and an evaluation in conditions similar to those found in several practical situations for many classes of materials, including cement‐based and ceramics. Traditional squeeze flow results are related to bulk normal force and height variation of a sample compressed between parallel plates. Additional information regarding boundary conditions at the interfaces or phenomena related to differential flow can be obtained through further instrumentation of the test. The combination of squeeze flow and a pressure mapping technique has been recently proposed, with great potential for the analysis of cement‐based materials and other granular suspensions. In this work, four mortars were evaluated by the pressure mapped squeeze flow (PMSF) method in two different displacement rates, and new ways to analyze the results were developed to expand the understanding of the flow through the technique, including plotting the pressure along multiple circumferences and an analysis of variation in each radial position. PMSF results were also compared to rotational rheometry and flow table tests for the first time, and concepts of interparticle separation were employed to discuss microstructural aspects of the flow. Due to the variety of mix designs (admixtures, particle size distribution, air content, water content, and other factors), the mortars presented diverse behaviors, ranging from primarily viscous or plastic flows to more granular responses (related to friction between particles with localized formation of jammed structures due to liquid phase migration). This work is part of an effort to establish a foundation for PMSF as a rheometric method that can be used for the analysis of a wide range of materials. [ABSTRACT FROM AUTHOR]

The high-frequency vibration and resonance of armature assembly in the hydraulic servo valve are the main reasons for instability and failure. Magnetic fluid (MF) operating in the squeeze mode can be taken as an effective damper for resonance suppression in the servo valve. Due to excitation difficulty and the low signal-to-noise ratio of high-frequency vibration signals, the capability of MF to modify multiple-order modal damping ratios in a multi-degree-of-freedom system is still unclear. To reveal the mechanism of magnetic fluid for improving modal damping ratios, an algorithm for modal damping ratio identification is proposed. The modal damping ratios of the armature assembly with and without magnetic fluid are identified based on the tested resonance free decay responses. Four resonance frequencies of armature assembly are observed, and the corresponding damping ratios are identified. The equivalent modal damping ratios due to squeeze flow of MF are obtained. The results show that the proposed algorithm can identify damping ratios with an accuracy of up to 98.79%. The damping ratios are improved by double or more due to the magnetic fluid, and the maximum resonance amplitudes are significantly reduced by 65.2% (from 916.5 μm to 318.6 μm). [ABSTRACT FROM AUTHOR]

Ice skates are remarkably slippery across a wide range of conditions. We propose, based on earlier observations and new modeling, that an ice-rich slurry forms rapidly beneath a skate blade during each stride to lubricate the interface. Crushing from normal load and abrasion from sliding provide ice particles and heat to the slurry, with average contact pressures approaching melting pressures for the bulk ice. Shearing of the slurry by forward motion generates additional heat to melt the ice particles at the pressure-reduced temperature. We model these mechanics and link the viscosity of the resulting slurry to its ice fraction, which controls slurry-film thickness via lateral squeeze-flow. The slurry properties quickly converge to establish a highly efficient lubricating film that provides the characteristically low skate friction across a wide range of conditions. Although our 1D model greatly simplifies the complex interaction mechanics, its predictions are insensitive to most assumptions other than the average contact pressure. The presence of ice-rich slurries supporting skates merges pressure-melting, crushing, abrasion and lubricating films as a unified hypothesis for why skates are so slippery across broad ranges of speeds, temperatures and normal loads. [ABSTRACT FROM AUTHOR]

We propose a methodology for the rheological characterization of a semisolid metal slurry using experimental squeeze-flow data. The slurry is modeled as a structural thixotropic viscoplastic material, obeying the regularized Herschel–Bulkley constitutive equation. All rheological parameters are assumed to vary with the structure parameter that is governed by first-order kinetics accounting for the material structure breakdown and build-up. The squeeze flow is simulated using finite elements in a Lagrangian framework. The evolution of the sample height has been studied for wide ranges of the Bingham and Reynolds numbers, the power-law exponent as well as the kinetics parameters of the structure parameter. Systematic comparisons have been carried out with available experimental data on a semisolid aluminum alloy (A356), where the sample is compressed from its top side under a specified strain of 80% at a temperature of 582 °C, while the bottom side remains fixed. Excellent agreement with the experimental data could be achieved provided that at the initial instances (up to 0.01 s) of the experiment, the applied load is much higher than the nominal experimental load and that the yield stress and the power-law exponent vary linearly with the structure parameter. The first assumption implies that a different model, such as an elastoviscoplastic one, needs to be employed during the initial stages of the experiment. As for the second one, the evolution of the sample height can be reproduced allowing the yield stress to vary from 0 (no structure) to a maximum nominal value (full structure) and the power-law exponent from 0.2 to 1.4, i.e., from the shear-thinning to the shear-thickening regime. These variations are consistent with the internal microstructure variation pattern known to be exhibited by semisolid slurries.

Abstract The rheometric techniques available for the evaluation of mortars involve a different set of flow conditions. Squeeze flow is based on the compression of the sample with gap reduction and geometric restrictions, providing important information even when phase separation occurs and an evaluation in conditions similar to those found in several practical situations for many classes of materials, including cement‐based and ceramics. Traditional squeeze flow results are related to bulk normal force and height variation of a sample compressed between parallel plates. Additional information regarding boundary conditions at the interfaces or phenomena related to differential flow can be obtained through further instrumentation of the test. The combination of squeeze flow and a pressure mapping technique has been recently proposed, with great potential for the analysis of cement‐based materials and other granular suspensions. In this work, four mortars were evaluated by the pressure mapped squeeze flow (PMSF) method in two different displacement rates, and new ways to analyze the results were developed to expand the understanding of the flow through the technique, including plotting the pressure along multiple circumferences and an analysis of variation in each radial position. PMSF results were also compared to rotational rheometry and flow table tests for the first time, and concepts of interparticle separation were employed to discuss microstructural aspects of the flow. Due to the variety of mix designs (admixtures, particle size distribution, air content, water content, and other factors), the mortars presented diverse behaviors, ranging from primarily viscous or plastic flows to more granular responses (related to friction between particles with localized formation of jammed structures due to liquid phase migration). This work is part of an effort to establish a foundation for PMSF as a rheometric method that can be used for the analysis of a wide range of materials.

This study dealt with an experimental squeeze-flow test between two parallel disks and rheological measurements using a rotational rheometer of pure bitumen and bitumen mixed with 10 and 20 wt.% kaolin without slip condition. The experimental procedure of the homogeneous samples' preparation was described. A steady-state and dynamic rheological analysis for pure bitumen and bitumen mixed with kaolin was detailed. Results show that pure bitumen and bitumen mixed with 10 wt.% kaolin at 26 °C correspond to a shear-thinning behavior. The effect of the kaolin particles becomes more critical at low shear rates than at high shear rates, where the matrix effect was dominant. The influence of temperature on bitumen mixed with 20 wt.% kaolin was investigated, and the obtained results show that the samples behave like a power-law model at 50 °C. Besides, the squeeze-flow test impact at an ambient temperature of 26 °C for pure bitumen and bitumen mixed with kaolin was also studied. Adding kaolin leads to a significant increase in viscosity and confirms the studied cases in the rheometry test at 26 °C. It was proven that pure bitumen and bitumen mixed with kaolin follow a power-law model at a specific range of shear rate. In particular, the decrease of the shear rate in bitumen mixed with 20 wt.% kaolin triggers the detection of the yield stress, which did not appear in the rheological measurements due to the applied deformation either in the shear and/or the elongational flow. [ABSTRACT FROM AUTHOR]

Portland cement and hydrated lime-based mortars are widely used in civil construction for covering and laying walls, sealing or structural restoration. However, the binders used in the production of mortar are produced in a way that is harmful to the environment, highlighting the need for alternative binders. In this work, the use of kaolinite plastic binder in mortars was evaluated, replacing hydrated lime with the material at levels of 0%, 50% and 100%. The importance of this study is to evaluate the feasibility of using an alternative binder in Portland cement and hydrated lime-based mortars. Fresh state properties were evaluated, such as consistency, squeeze flow and density in the fresh state; in addition to properties in the hardened state, such as compressive strength, water absorption, x-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization results of kaolinite plastic binder (D10 = 0.00009 mm and D60 = 0.0004 mm) show that the material has a particle size closer to hydrated lime (D10 = 0.00001 mm and D60 = 0.0004 mm), than Portland cement and quartz sand, evidenced by parameters D10 and D60. Additionally, the kaolinite plastic binder presents moderate pozzolanicity, indicating the feasibility of being used in this type of application. The workability tests show that kaolinite plastic binder has the potential to improve the workability of the mortar. In dynamic tests (consistency) it was observed that the 100% kaolinite plastic binder composition is viable as it promotes an increase in spread from 253 to 265 mm. In static tests (squeeze flow) the composition with 50% kaolinite plastic binder showed the best spreading results, with values of 10.7 mm, while the compositions containing 0% and 100% showed spreading of 8.97 and 7.40 mm, respectively. This demonstrates the potential for using kaolinite plastic binder in mortars. The hardened state results, such as compressive strength and water absorption, were also satisfactory. Although the compressive strength values showed a reduction with the use of kaolinite plastic binder, the values reached 7.5 MPa after 28 days, which is compatible with the proposed application. Finally, it was observed from the results of XRD and SEM that the kaolinite plastic binder shows adhesion with the hydration products of the Portland cement in the mortar, promoting a reduction in ettringite and portlandite due to its moderate pozzolanicity. Based on these results, it is possible to conclude that kaolinite plastic binder is a viable substitute for hydrated lime in mortars. [Display omitted] • Workability tests show that kaolinite plastic binder improves the workability of the mortar. • Kaolinite plastic binder shows adhesion with the hydration products of the Portland cement in the mortar. • Kaolinite plastic binder is a viable substitute for hydrated lime in mortars. [ABSTRACT FROM AUTHOR]

The high-frequency vibration and resonance of armature assembly in the hydraulic servo valve are the main reasons for instability and failure. Magnetic fluid (MF) operating in the squeeze mode can be taken as an effective damper for resonance suppression in the servo valve. Due to excitation difficulty and the low signal-to-noise ratio of high-frequency vibration signals, the capability of MF to modify multiple-order modal damping ratios in a multi-degree-of-freedom system is still unclear. To reveal the mechanism of magnetic fluid for improving modal damping ratios, an algorithm for modal damping ratio identification is proposed. The modal damping ratios of the armature assembly with and without magnetic fluid are identified based on the tested resonance free decay responses. Four resonance frequencies of armature assembly are observed, and the corresponding damping ratios are identified. The equivalent modal damping ratios due to squeeze flow of MF are obtained. The results show that the proposed algorithm can identify damping ratios with an accuracy of up to 98.79%. The damping ratios are improved by double or more due to the magnetic fluid, and the maximum resonance amplitudes are significantly reduced by 65.2% (from 916.5 μm to 318.6 μm).

In bonding processes, the final distribution of the adhesive in the gap depends on the compressing normal load, velocity and kinematics, the adhesive properties, but above all on the initial adhesive distribution. The latter is also largely responsible for trapped air and the adhesive squeezes out at the edges. A model has recently been developed for the simulation of the flows during compression processes in adhesively bonded joints. This paper extends the aforementioned model towards shear rate-dependent viscosity, a phenomenon crucial for most industrial adhesives. Besides the assumption of a Newtonian fluid, approximations of a power-law and a Yasuda law are used. For this purpose, a further subordinate Newton method for determining the flow profiles is added to the existing model. Rheological measurements over a wide range of shear rates serve as a reference. For the verification, studies are performed on two academic examples: a rectangular, and a circular propagation. The results are compared with analytical solutions and CFD simulations. A very good agreement of pressure (deviations below 1.5%), and velocity profiles (deviations below 5%), for all scenarios and flow laws, was found. The long-term goal of this model development is the prediction of adhesive compression flows for complex application patterns. [ABSTRACT FROM AUTHOR]

The technological performance and environmental advantages of replacing sand by ornamental stone processing waste (OSPW) in the production of mortars for civil construction were studied. Technological properties associated with the standard consistency index, squeeze flow and bulk densities as well as the determination of water retention and calorimetry analysis were evaluated in the mortars' fresh state, whereas capillarity tests as well as mechanical resistance by flexural and compression tests were determined in the hardened state for mortars incorporated with 10, 30 and 60 wt.% of OSPW substituting sand. Three different types of Portland Cements were considered in the incorporated mortars production. For these mortars environmental analysis, their corresponding life cycle assessment results were compared to that of conventional waste-free (0% OSPW) control mortar. It was found that the OPSW incorporation acts as nucleation sites favoring a hydration process, which culminates after 28 days of curing in the formation of more stable phases identified as hydrated calcium silicates by X-ray diffraction (XRD) amorphous halo. It was also revealed that both flexural and compression improved resistance for the incorporated mortars after 28 curing days. In particular, the calorimetry and XRD results explained the better mechanical resistance (12 MPa) of the 30 wt.% OSPW incorporated mortar, hardened with Portland Cement V, compared not only to the control, but also to the other incorporated mortars. As for the environmental analysis, the replacement of sand by OSPW contributed to the reduction in associated impacts in the categories of land use (−5%); freshwater eutrophication (−9%); marine eutrophication (−6%) and global warming (−5%). [ABSTRACT FROM AUTHOR]

Installing flue gas desulphurization systems before particulate collectors in thermoelectric plants generates spray dryer ash (SDA), a mixture of fly ash and sulfur products. SDA carries a large environmental liability, and research to exploit this waste is still incipient. An alternative use for SDA is as raw material for civil construction. Therefore, the objective of this article is to verify the feasibility of replacing hydrated lime with SDA in rendering mortars for façades, and using SDA as a mineral addition to concrete. For this, mortar mixes with 0%, 33%, 67%, and 100% SDA replacement contents were prepared, and tests in fresh and hard states performed. For concrete, mixes with 0%, 5%, 10%, and 20% of SDA added to the cement mass were prepared, and mechanical and durability tests performed. Results show that mortar consistency tends to increase with SDA content, decreasing its workability. Mechanical and durability properties are equal to or higher than those of the reference mix, both in concrete and mortar. Also, mortar with 67% of SDA performs the best. [ABSTRACT FROM AUTHOR]

Squeeze flow is used for rheological evaluation of many classes of materials. It can be performed in different configurations and is particularly interesting for heterogeneous materials that go through similar conditions during practical application. The assessment of pressure distribution during the test can provide additional information about flow conditions. For that reason, Pressure Mapped Squeeze Flow (PMSF) has been previously presented and is employed in this work with constant volume configuration for the first time. Cement-based mortars were examined, four formulated in laboratory with differences regarding the presence or not of cellulose ether admixture and hydrated lime, and one factory-produced mortar. Bulk squeeze flow results are analyzed in parallel with raw pressure distribution images. The evolution of the area as measured by the sensor is contrasted with the constant volume hypothesis. Pressure distribution calibrated results are compared to predictions from theoretical models. Flow induced microstructural changes indicated by the obtained results are explained based on the concept of interparticle spacing. The method can be useful for the rheological analysis of heterogeneous materials under partially confined flow. [Display omitted] • Pressure Mapped Squeeze Flow of cement mortars in constant volume configuration • New evidence of phase separation and the influence of material composition • Tracking of sample area and volume change during the test, relevant for modelling. • Phase separation induces transition from plastic/viscous flow to granular behavior. • Analysis of flow induced microstructural changes supported by interparticle spacing. [ABSTRACT FROM AUTHOR]

The essential element of this paper is to research the porous and squeezed characteristics of time varying heats that modify the flow speed and enhance the refrigerating/boiling performance of the materials, optimize the tracers flows and minimalized instability in the non-Newtonian fluids. In the presence of no-slip velocity and convective circumstances, squeezing disks tempting laminar, unsteady and incompressible non-Newtonian fluid. The convective formulation for the equations of Navier Stokes, energy and concentration are modeled on flat disks to investigate and execute both analytical and numerical analysis of heat flow and mass transfer, which transmuted further into extremely non-linear system of ordinary differential equation with the help of similarity transformations. Regarding smears, self-similar equations with adequate starting estimates and supporting parameters are resolved by utilizing the Homotopy Analysis Method (HAM) to generate an expedited and guaranteed convergence procedure. Comparisons between HAM and the BVP4c numerical solver program demonstrate the validity and precision of HAM results. It is found by increasing or decreasing the Hartman number reduces the capillary area, making the Lorentz force influence quite visible for small non-Newtonian parameter. The concentration rate at the lower end disk rises rapidly as the thermal diffusivity rises. The radial velocity also declines because of the rise in the outflow rate from the flow domains. The suction parameter also declines. Additionally, increasing the parameter of non-Newtonian enhances the flow of temperature/mass and skin friction. In the suction/injection case, all physical factors have a reverse influence upon fluid flow patterns.

The present work evaluated the applicability of the direct shear test of soils (ASTM D 3080) as an alternative for the rheological characterization of masonry mortars. The sensitivity analysis of the method for mortars was carried out by varying the particle size distribution of the sand and the water/dry material ratio, generating twelve different mixtures. In addition to a basic characterization, the shear test results were compared with those of the squeeze-flow test (ABNT NBR15839). For squeeze-flow, 24 tests were carried out with two speeds (0.1 and 3 mm/s), and for direct shear, 48 tests were carried out with 4 normal stresses (13.5, 25, 50, and 100 KPa). It is concluded that the direct shear test, using cohesion and friction angle parameters, demonstrated the ability to adequately characterize the complex behavior of plastic mortars and the sensitivity to variations in the mixture. A linear correlation was found between the friction angle (shear test) and the consistency index (flow table), with R2 = 0,87. Furthermore, for high plasticity mortars, was found a non-linear correlation between compression flow (squeeze flow) and cohesion (direct shear test), with R2 = 0,67. • A shear box test of soils approach for rheometry of masonry mortars is proposed. • The direct shear test demonstrated the ability to characterize plastic mortars. • Shear test is sensitive to variations in particle size of sand and amount of water. • The direct shear test can determine two parameters: cohesion and angle of friction. • Correlations were found between the shear test and other methods used for mortars. [ABSTRACT FROM AUTHOR]

Ferroliquids are an example of a colloidal suspension of magnetic nanomaterials and regular liquids. These fluids have numerous applications in medical science such as cell separation, targeting of drugs, magnetic resonance imaging, etc. The hybrid nanofluid is composed by scattering the magnetic nanomaterial of more than one type nanoparticles suspended into the base fluid. It has different scientific applications such as heat dissipation, dynamic sealing, damping, etc. Owing to the vast ferrofluid applications, the time-dependent squeezed flow of hybrid ferroliquids under the impact of non-linear radiation and mixed convection within two disks was explored for the first time in this analysis. Here, the cobalt and magnetite ferrofluids are considered and scattered in a 50%:50% mixture of water–EG (ethylene glycol). The similarity technique is used to reduce the leading PDEs into coupled non-linear ODEs. The transmuted equations together with recommended boundary restrictions are numerically solved via Matlab solver bvp4c. The opposing and assisting flows are considered. The impacts of an emerging parameter on fluid velocity and temperature field of hybrid ferroliquids are examined through the different graphical aids. The results showed that the opposite trend is scrutinized due to the magnetic influence on the temperature and velocity in the case of assisting and opposing flows. The velocity augments due to the volume fraction of nanoparticles in the assisting flow and declines in the opposing flow, while the opposite direction is noticed in the temperature field.

In this work we develop a void filling and void motion dynamics model using volatile pressure and squeeze flow during tape placement process. The void motion and filling are simulated using a non-local model where their presence is reflected in the global macroscale behavior. Local pressure gradients during compression do play a critical role in void dynamics, and hence the need for a non-local model. Deriving a non-local model accounting for all the void motion and dynamics entails a prohibitive number of degrees of freedom, leading to unrealistic computation times with classical solution techniques. Hence, Proper Generalized Decomposition – PGD – is used to solve the aforementioned model. In fact, PGD circumvents the curse of dimensionality by using separated representation of the space coordinates. For example, a 2D problem can be solved as a sequence of 1D problems to find the 2D solution. The non-local model solution sheds light on the fundamental of the void dynamics including their pressure variation, motion and closure mechanisms. Finally, a post treatment of the transient compression of the voids is used to derive conclusions regarding the physics of the void dynamics. [ABSTRACT FROM AUTHOR]

Nanofluids have the ability to flow smoothly in micro-cavities in addition with scattering of the nanoparticles. Because of the good convection between nanoparticles and the base fluid, nanofluids can achieve a good thermal conductivity. The main advantages of adding nanosize particles with base fluid are to improve the ability of storing heat, effective surface area, heat transmission, collisions and interaction among the nanoparticles. The main aim of this research work is to examine the steady and incompressible nanofluid flow between parallel rotating plates. Viscose and joule dissipation effects are taken into account. To our knowledge, impact of electrical MHD and Hall effect with Cattaneo–Christov heat flux on the squeezing 3-D flow nanofluid between parallel rotating plates are not examined yet. Heat in the form of Cattaneo–Christov heat flux is applied. We used similarity transformations to transform the primary equations to a system of ordinary differential equations (ODEs). These ODEs are then solved through the standard procedure of homotopy analysis technique. The skin friction and Nusselt number are numerically tabulated under the influence of some focused parameters. The effects produced by different parameters on the velocity (components) and temperature profiles are graphically depicted and explained in a bit detail. [ABSTRACT FROM AUTHOR]

The transient, axisymmetric squeeze flow of the non-Newtonian shear thinning material between finite disks is studied numerically. The fluid between disks is assumed to follow the Carreau-Bird model. Two disks approach each other at a constant velocity while no-slip boundary condition is assumed. The time dependent simulation shows the effect of fluid nonlinearity, flow parameters and geometric aspect ratio on the flow dynamic and evolution of squeeze force. Also, some physical phenomena are shown and are explained at the edge of the disks and out of them. The conservation and momentum equations containing inertia effects are solved using moving mesh scheme and finite volume method. The SIMPLE algorithm is used to solve the pressure-velocity coupling. [ABSTRACT FROM AUTHOR]

Magnetorheological fluid has been investigated intensively nowadays, and magnetorheological fluid shows large force capabilities in squeeze mode with wide application potential such as control valve, engine mounts, and impact dampers. In these applications, magnetorheological fluid is flowing in a dynamic environment due to the transient nature of inputs and system characteristics. Hence, this article undertakes a comprehensive study of magnetorheological fluid squeeze flow dynamics behaviors with wall slip, yield, and inertia. First, the dynamic model with the bi-viscous constitutive of magnetorheological fluid squeeze flow including wall slip and inertial force is presented. Then, the mathematical model is validated, matching magnetorheological fluid squeeze dynamic test results very well. Finally, the dynamics behavior and mechanism of magnetorheological fluid squeeze flow with inertia, yield, and wall slip are explored. Results show that (1) increasing yield stress and decreasing initial gap will increase the magnetorheological fluid vertical force greatly; (2) the wall slip affects the yield surface of magnetorheological fluids in the squeeze zone and affects the squeeze force; (3) the inertial force is increasing tremendously as the increased excitation frequency and yield stress and should be included with high-frequency excitation or yield stress. [ABSTRACT FROM AUTHOR]

In the manufacturing industry, the process of applying adhesive to join two substrates can be challenging. It requires precise placement of adhesive so that it is distributed in the desired pattern, ensuring a strong bond between the substrates. Overfilling is a common practice to ensure that the bond is not underfilled after the substrates are pressed together. However, this approach leads to unnecessary adhesive waste and can result in additional cleaning work. To address these issues, an optimization algorithm has been developed that can compute an initial adhesive pattern to flow into any desired geometry. The algorithm is based on a transient squeeze flow simulation, which iteratively removes fluid material as it flows out of the target bond domain. For example, to obtain a square bond geometry after a parallel squeezing process, the adhesive needs to be initially applied in a star shape. However, the algorithm is highly adaptable and can be used for many desired bond geometries as shown in this paper. The results are independent of the mesh resolution and fluid flow law, thus eliminating the need for complex rheological fluid characterization. The algorithm requires only two input parameters, namely the target bond geometry and the degree of compression. This highly simplifies the adaption of the proposed optimization method for manufacturers, and their design requirements can be considered with ease. The results are reliable and consistent despite the simulation's complexity. Overall, this new optimization methodology represents a significant advance in adhesive application technology, eliminating the need of overfilling and thus making the manufacturing process more efficient, sustainable and cost-effective. [ABSTRACT FROM AUTHOR]

In this paper, we studied the squeeze flow between circular disks of a new class of fluids defined by an implicit relation referred to as stress power law fluids. The constitutive response of these fluids was written expressing the symmetric part of the velocity gradient as a tensorial function of the Cauchy stress. We assumed that the aspect ratio between the gap separating the disks and the radius was small so that a lubrication expansion could be adopted. We wrote the general problem and looked for a solution that could be written in terms of the small aspect ratio parameter. We obtained a sequence of problems that could be solved iteratively at each order, and we focused on the leading and first order, deriving explicit expressions for the velocity field, stress, and pressure.

Automated tape placement - ATP - is a recent manufacturing technology for composite materials. Therefore, a correct modeling of the multi-physical process is critical in order to make possible in-situ consolidation. In this work, we propose an accurate modelling framework and an efficient simulation procedure of physics occurring during the process with the aim of studying the influence of material and process parameters into the material consolidation evolution. For that purpose, an accurate description of the prepreg surface becomes compulsory, justifying the use of a multi-resolution description of it based on the use of wavelets. [ABSTRACT FROM AUTHOR]

• The axisymmetric squeeze flow of a viscoplastic Casson material is studied. • The no-slip and threshold stick-slip boundary conditions are considered. • We develop an asymptotic solution. • Numerical solution is done by Accelerated proximal gradient and Augmented Lagrangian methods. We develop an asymptotic solution for the axisymmetric squeeze flow of a viscoplastic Casson medium following the asymptotic technique suggested earlier by Balmforth and Craster (1999) and Frigaard and Ryan (2004). The no-slip and slip yield boundary conditions at the wall are considered. Depending on the ratio of two dimensionless parameters partial slip (stick-slip) or full slip at the wall (slip) are possible. We confirm numerically obtained solution, using Accelerated proximal gradient and Augmented Lagrangian methods. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The aim of this research was to evaluate the influence of the curauá or polypropylene fibers on rheological properties of fresh cementitious paste. The variables were the percentage of fiber content 1 wt% or 2 wt% and the length of the curauá or polypropylene fibers: 6 or 10 mm, but it was also prepared paste without fibers as reference. Squeeze flow and ram extrusion tests were carried out to analyze the flow of the pastes. The hardened paste was evaluated by X-ray microtomography to observe the orientation of the fibers inside the paste. Curauá fiber led to higher force of extrusion and lower displacement of the fresh cement paste at the squeeze flow test and increased the pressure at the ram extrusion test in relation to polypropylene fibers, independently of the content and length. However, length of the same fiber presented higher influence on mixture flow than fiber content. [ABSTRACT FROM AUTHOR]